List Journal
Early-Type Related * The Dawn of the Red: star formation histories of group galaxies over the past 5 billion years ** McGee, Balogh, Wilman, Bower, Mulchaey, Parker & Oemler 2011, MNRAS ** ' The evolution of passive fraction in groups between z= 0.4 and 0 is consistent with a simple accretion model, in which galaxies are environmentally affected 3 Gyr after falling into a ~10^13 M_sun group.' * The Assembly of the Red Sequence at z ~ 1: The Color and Spectral Properties of Galaxies in the Cl1604 Supercluster ** Lemaux, Gal, Lubin, Kocevski, Fassnacht, McGrath, Squires, Surace & Lacy 2012, ApJ ** Nearly all of the brightest and most massive red-sequence galaxies present in the supercluster environment are found to lie within the bounds of the cluster and group systems, with a surprisingly large number of such galaxies present in low-mass group systems. Despite the prevalence of these red-sequence galaxies, we find that the average cluster galaxy has a spectrum indicative of a star-forming galaxy, with a star formation rate between those of z ~ 1 field galaxies and moderate-redshift cluster galaxies. * The progenitors of present-day massive red galaxies up to z ≈ 0.7 - finding passive galaxies using SDSS-I/II and SDSS-III ** Tojeiro, Percival, Wake, Maraston, Skibba, Zehavi et al. 2012, MNRAS ** When weighting the BOSS galaxies based on the predicted properties of the LRGs, and restricting the analysis to the reddest BOSS galaxies, we find an evolution of the large-scale clustering that is consistent with dynamical passive evolution, assuming a standard cosmology. * Stellar Populations of Elliptical Galaxies in the Local Universe ** Zhu, Blanton & Moustakas 2012, ApJ ** We study the stellar populations of 1923 elliptical galaxies at z < 0.05 selected from the Sloan Digital Sky Survey as a function of velocity dispersion, σ, and environment. * The evolution of early-type galaxies selected by their spatial clustering ** Padilla, Christlein, Gawiser & Marchesini 2011, A&A ** The comparison between high-redshift ETGs and their likely descendants at z = 0 points to a higher number density for the progenitors by a factor 5.5 ± 4.0, implying the need for mergers to decrease their number density by today. Because the luminosity densities of progenitors and descendants are consistent, our results show no need for significant star-formation in ETGs since z = 1, which indicates that the needed mergers are dry, i.e. gas free. * Evolution of Quiescent and Star-forming Galaxies since z ~ 1.5 as a Function of their Velocity Dispersions ** Bezanson, van Dokkum & Franx 2012, ApJ ** We show that our results are qualitatively consistent with a simple model in which star-forming galaxies quench and are added to the quiescent population. In order to compensate for the migration into the quiescent population, the velocity dispersions of star-forming galaxies must increase, with a rate that increases with dispersion. * The Pair Fraction of Massive Galaxies at 0 <= z <= 3 ** Man, Toft, Zirm, Wuyts & van der Wel 2012, ApJ ** This is a hint that mechanism(s) other than major merging may be required to increase the sizes of the massive, compact quiescent galaxies from z ~ 2 to 0. * Characterizing the satellites of massive galaxies up to z ˜ 2: young populations to build the outskirts of nearby massive galaxies ** Marmol-Queralto, Trujillo, Villar, Barro & Perez-Gonzalez 2012, MNRAS ** We find that the satellites have bluer colours than their central galaxies. When exploring the stellar ages of the galaxies, we find that the satellites have similar ages to the massive galaxies that host them at high redshifts, while at lower redshifts they are, on average, ≳1.5 Gyr younger. * Further Evidence for Large Central Mass-to-light Ratios in Early-type Galaxies: The Case of Ellipticals and Lenticulars in the A262 Cluster ** Wegner, Corsini, Thomas, Saglia & Bender 2012, AJ ** The dynamical mass that follows the light is larger than expected for a Kroupa stellar initial mass function (IMF), especially in galaxies with high velocity dispersion σ_eff inside the effective radius r_eff. * Relaxation and stripping - The evolution of sizes, dispersions and dark matter fractions in major and minor mergers of elliptical galaxies ** Hilz, Naab, Ostriker, Thomas, Burkert & Jesseit 2012, MNRAS ** Our results indicate that minor mergers of galaxies embedded in massive dark matter haloes provide a potential mechanism for explaining the rapid size growth and the build-up of massive elliptical systems predicting significant dark matter fractions and radially biased velocity dispersions at large radii. * Close companions to brightest cluster galaxies: support for minor mergers and downsizing ** Edwards & Patton 2012, MNRAS ** We conclude that the luminosity of bound merger candidates down to luminosity ratios of 20:1 could be adding as much as 10 per cent to the mass of a typical BCG over 0.5 Gyr at redshifts of z ˜ 0.3. * The Diminishing Importance of Major Galaxy Mergers at Higher Redshifts ** Williams, Quadri & Franx 2011, ApJ ** Thus, even though other studies find major mergers to be relatively uncommon since z = 1, our results suggest that few additional mergers occur in the 1 < z < 2 range and other mechanisms may be required to explain the mass and size growth of galaxies over this epoch. * Superdense Galaxies and the Mass-Size Relation at Low Redshift ** Poggianti, Calvi, Bindoni, D'Onofrio, Moretti, Valentinuzzi et al. 2013, ApJ ** When stellar age and environmental effects are taken into account, the average amount of size evolution of individual galaxies between high and low z is mild, a factor ~1.6. * The dominant role of mergers in the size evolution of massive early-type galaxies since z~1 ** Lopez-Sanjuan, Le Fevre, Ilbert, Tasca, Bridge, Cucciati et al. 2012, A&A ** Our results show that massive ETGs have undergone 0.89 mergers (0.43 major and 0.46 minor) since z~1, leading to a mass growth of ~30%. We find that μ≥1/10 mergers can explain ~55% of the observed size evolution of these galaxies since z ~ 1. * A Strongly Lensed Massive Ultracompact Quiescent Galaxy at z ~ 2.4 in the COSMOS/UltraVISTA Field ** Muzzin, Labbe, Franx, van Dokkum, Holt, Szomoru et al. 2012, ApJ ** This is typical of massive "red-and-dead" galaxies at this redshift and confirms that this source is the first bona fide strongly lensed massive ultracompact quiescent galaxy to be discovered. * Deep Absorption Line Studies of Quiescent Galaxies at z ~ 2: The Dynamical-mass-Size Relation and First Constraints on the Fundamental Plane ** Toft, Gallazzi, Zirm, Wold, Zibetti, Grillo & Man 2012, ApJ ** The galaxy formed the majority of its stars at z > 3 and currently has little or no ongoing star formation. * What Determines the Sizes of Red Early-type Galaxies? ** Lee, Kim, Ree, Kim et al. 2013, ApJ ** These results indicate that the sizes of intermediate- and high-mass red early-type galaxies are significantly affected by their recent minor mergers or rotations, whereas the sizes of low-mass red early-type galaxies are affected by some other mechanisms. Major dry mergers also seem to have influenced on the size growth of high-mass red early-type galaxies. * Dry minor mergers and size evolution of high-z compact massive early-type galaxies ** Oogi & Haba 2013, MNRAS ** We show that sequential minor mergers of compact satellite galaxies are the most efficient at promoting size growth and decreasing the velocity dispersion of compact massive ETGs in our simulations * Size evolution of spheroids in a hierarchical Universe ** Shankar, Marulli, Bernardi, Mei, Meert & Vikram 2013, MNRAS ** The model also predicts that central spheroids living in more massive haloes tend to have larger sizes at fixed stellar mass. Including host halo mass dependence in computing velocity dispersions allows the model to properly reproduce the correlations with stellar mass. * The evolution of the mass-size relation for early-type galaxies from z~1 to the present: dependence on environment, mass range and detailed morphology ** Huertas-Company, Mei, Shankar, Delaye, Raichoor et al. 2013, MNRAS' ** The galaxy mass-size relation and size growth do not depend on environment in the halo mass range explored in this work * The ATLAS3D project - XVII. Linking photometric and kinematic signatures of stellar discs in early-type galaxies ** Krajnovic, Alatalo, Blitz, Bois, Bournaud, Bureau, Cappellari et al. 2012, MNRAS ** The decomposition into discs and bulges can be used as a rough approximation for the separation between fast and slow rotators, but it is not a substitute, as there is only a 59 per cent probability to correctly recognize slow rotators. * Shape Evolution of Massive Early-type Galaxies: Confirmation of Increased Disk Prevalence at z>1 ** Chang, van der Wel, Rix, Wuyts, Zibetti, Ramkumar & Holden 2013, ApJ ** Merging is a plausible mechanism that can explain both results: at all epochs, merging is required for early-type galaxies to grow beyond log(M/M☉)~11.3, and all early types over time gradually and partially lose their disk-like characteristics. * Globular cluster systems as tracers of environmental effects on Virgo early-type dwarfs ** Sanchez-Janssen & Aguerri 2012, MNRAS ** Our analysis does not favour violent evolutionary mechanisms that result in significant stellar mass-losses, but more gentle processes involving gas removal by a combination of internal and external factors, and highlights the relevant role of initial conditions. * Early-type Galaxies at z = 1.3. I. The Lynx Supercluster: Cluster and Groups at z = 1.3. Morphology and Color-Magnitude Relation ** Mei, Stanford, Holden, Raichoor, Postman et al. 2012, ApJ ** ' The ETG mass-size relation shows evolution toward smaller sizes at higher redshift in both clusters and groups, while the late-type mass-size relation matches that observed locally. When compared to the clusters, the group ETG red sequence shows lower zero points (at ~2σ) and larger scatters, both expected to be an indication of a younger galaxy population.' Morphology, Structures and other Basic Properties * Quenching Star Formation at Intermediate Redshifts: Downsizing of the Mass Flux Density in the Green Valley ** Goncalves, Martin, Menendex-Delmestre, Wyder & Koekemoer 2012, ApJ ** we are able to infer the star formation histories of these objects and measure the stellar mass flux density transiting from the blue cloud to the red sequence when the universe was half its current age. * AEGIS: The Morphologies of Green Galaxies at 0.4 < z < 1.2 ** Mendez, Coil, Lotz, Salim, Moustakas & Simard 2011, ApJ ** Our results show that green galaxies are generally massive (M * ~ 1010.5 M sun) disk galaxies with high concentrations. We conclude that major mergers are likely not the sole mechanism responsible for quenching star formation in this population and that either other external processes or internal secular processes play an important role both in driving gas toward the center of these galaxies and in quenching star formation. * The Environmental Dependence of the Incidence of Galactic Tidal Features ** Adams, Zaritsky, Sand, Graham, Bildfell et al. 2012, AJ ** Regardless of the method used to classify tidal features, or the fidelity imposed on such classifications, we find a deficit of tidally disturbed galaxies with decreasing clustercentric radius that is most pronounced inside of ~0.5 R_200. * Revealing Velocity Dispersion as the Best Indicator of a Galaxy's Color, Compared to Stellar Mass, Surface Mass Density, or Morphology ** Wake, van Dokkum & Franx 2012, ApJ ** Overall σ is the best indicator of a galaxy's typical color, showing the largest residual color dependence when any of the other three parameters are fixed, and M star is the poorest. * The Impact of Interactions, Bars, Bulges, and Active Galactic Nuclei on Star Formation Efficiency in Local Massive Galaxies ** Saintonge, Tacconi, Fabello, Wang, Catinella, Genzel et al. 2012, ApJ ** We find no link between the presence of AGNs and these long depletion times. In the regime where galaxies are disk-dominated and gas-rich, the galaxies undergoing mergers or showing signs of morphological disruptions have the shortest molecular gas depletion times, while those hosting strong stellar bars have only marginally higher global star formation efficiencies as compared to matched control samples. * The Dependence of Quenching upon the Inner Structure of Galaxies at 0.5 <= z < 0.8 in the DEEP2/AEGIS Survey ** Cheung, Faber, Koo, Dutton, Simard, McGrath, Huang, Bell et al. 2012, ApJ ** suggesting that the innermost structure of galaxies is most physically linked with quenching. * What Turns Galaxies Off? The Different Morphologies of Star-forming and Quiescent Galaxies since z ~ 2 from CANDELS ** Bell, van der Wel, Papovich, Kocevski, Lotz, McIntosh et al. 2012, ApJ ** Noting the rarity of quiescent galaxies without prominent bulges, we argue that a prominent bulge (and perhaps, by association, a supermassive black hole) is an important condition for quenching star formation on galactic scales over the last 10 Gyr, in qualitative agreement with the active galactic nucleus feedback paradigm. * On the Shapes and Structures of High-redshift Compact Galaxies ** Chevance, Weijmans, Damjanov, Abraham, Simard, et al. 2012, ApJ ** ' The mismatch between the properties of high-redshift compact galaxies and those of both local early-type and disk-dominated systems leads us to conclude that the basic structures of high-redshift compact galaxies probably do not closely resemble those of any single local galaxy population.' * Approximate Bayesian Computation for astronomical model analysis: a case study in galaxy demographics and morphological transformation at high redshift ** Cameron & Pettitt 2012, MNRAS ** our ABC analysis of the high-redshift morphological mix returns tight constraints on the evolving merger rate in the early Universe and favours major merging (with disc survival or rapid reformation) over secular evolution as the mechanism most responsible for building up the first generation of bulges in early-type discs. * The sizes, masses and specific star formation rates of massive galaxies at 1.3 < z < 1.5: strong evidence in favour of evolution via minor mergers ** McLure, Pearce, Dunlop, Cirasuolo, et al. 2013, MNRAS ** we find that a scenario in which mass accretion is dominated by minor mergers can comfortably produce the necessary evolution, whereby an increase in stellar mass of only a factor of ≃2, accompanied by size growth of a factor of ≃3.5 * Structural Parameters of Galaxies in CANDELS ** van der Wel, Bell, Haussler, McGarth, Chang, Guo, McIntosh, Rix et al. 2012, ApJS ** global structural parameter measurements of 109,533 unique, H F160W-selected objects from the CANDELS multi-cycle treasury program. Sérsic model fits for these objects are produced with GALFIT in all available near-infrared filters (H F160W, J F125W and, for a subset, Y F105W). * The morphologies of massive galaxies at 1 < z < 3 in the CANDELS-UDS field: compact bulges, and the rise and fall of massive discs ** Bruce, Dunlop, Cirasuolo, McLure, Targett, Bell et al. 2012, MNRAS ** ' while our results show that the massive galaxy population is undergoing dramatic changes at this crucial epoch, they also suggest that the physical mechanisms which quench star formation activity are not simply connected to those responsible for the morphological transformation of massive galaxies into present-day giant ellipticals.' Ultra-Compact Dwarf Galaxies * A catalog of extended clusters and ultra-compact dwarf galaxies. An analysis of their parameters in early- and late-type galaxies by Bruns & Kroupa 2012 ** Astronomy & Astrophysics, Volume 547, id.A65, 17 pp SDSS Related * Galaxy Growth by Merging in the Nearby Universe ** Jiang, Hogg & Blanton 2012, ApJ ** One conclusion of this work is that if the total growth of red galaxies from z = 1 to z = 0 is mainly due to merging, the merger rates must have been higher in the past. * A Stellar Mass Threshold for Quenching of Field Galaxies ** Geha, Blanton, Yan & Tinker 2012, ApJ ** The fraction of quenched dwarf galaxies decreases rapidly with increasing distance from a massive host, leveling off for distances beyond 1.5 Mpc. * The Nature of LINER-like Emission in Red Galaxies ** Yan & Blanton 2012, ApJ ** We conclude that the line emission in most LINER-like galaxies found in large-aperture (>100 pc) spectroscopy is not primarily powered by AGN activity and thus does not trace the AGN bolometric luminosity. However, they can be used to trace warm gas in these red galaxies. * Luminosity and stellar mass functions of discs and spheroids in the SDSS and the supermassive black hole mass function ** Benson, Dzanovic, Frenk & Sharples 2007, MNRAS ** We find that stars in discs contribute 35-51 per cent of the local stellar mass density. * idal streams around galaxies in the SDSS DR7 archive. I. First results ** Miskolczi, Bomans & Dettmar 2011, A&A ** ' At least 6% of the galaxies show distinct stream like features, a total of 19% show faint features.' * The Relation between Galaxy Morphology and Environment in the Local Universe: An RC3-SDSS Picture ** Wilman & Erwin 2012, ApJ ** This suggests two channels for forming S0 galaxies: one which operates for central galaxies and another which transforms lower-mass ( M*<10^11 M_sun) accreted spirals into satellite S0 galaxies in massive halos. * Observed versus modelled u-, g-, r-, i-, z-band photometry of local galaxies - evaluation of model performance ** Hansson, Lisker & Grebel 2012, MNRAS ** Using our preferred model we find that the star formation history, metallicity and also dust content can be constrained over a large part of the parameter space through the use of u-, g-, r-, i-, z-band photometry. However, strong local degeneracies are present due to overlap of models with high and low extinction in certain parts of the colour space. * The Suppression of Star Formation and the Effect of the Galaxy Environment in Low-redshift Galaxy Groups ** Rasmussen, Mulchaey, Bai, Ponman & Raychaudhury 2012, ApJ ** The results favor an average quenching timescale of >~ 2 Gyr and strongly suggest that a combination of tidal interactions and starvation is responsible. ' * The role of stellar mass and environment for cluster blue fraction, AGN fraction and star formation indicators from a targeted analysis of Abell 1691 ** Pimbblet & Jensen 2012, ''MNRAS ** ''' the duty cycle of high- and low-mass cluster galaxies is markedly different, with a significant departure in star formation and specific star formation rates observed beyond r_200 * The fraction of early-type galaxies in low-redshift groups and clusters of galaxies ** Hoyle, Masters, Nichol, Jimenez & Bamford 2012, MNRAS ** Our results suggest that most morphological transformation is happening on the group scale before groups merge into massive clusters. However, we show that within each halo a morphology-density relation remains: it is summing the total fraction to a self-similar scaled radius which results in a flat morphology-halo mass relationship. * Astrophysically motivated bulge-disc decompositions of Sloan Digital Sky Survey galaxies ** Lackner & Gunn 2012, MNRAS ** Using our galaxy classifications, we find that Petrosian concentration is a good indicator of bulge-to-total ratio, while overall Sérsic index is not. Additionally, we find that the majority of green valley galaxies are bulge+disc galaxies. * The effect of environment on discs and bulges ** Lackner & Gunn 2012, MNRAS ** Our results add to the evidence that star formation is quenched in group environments, instead of clusters, and that star formation quenching and morphological transformation are separate processes. * Dust Attenuation in Disk-dominated Galaxies: Evidence for the 2175 Å Dust Feature ** Conroy, Schiminovich & Blanton 2010, ApJ ** These results also imply a very weak dependence of the FUV-NUV color on total FUV attenuation, and we conclude from this that it is extremely difficult to use only the observed UV spectral slope to infer the total UV dust attenuation, as is commonly done. Galex-Arecibo-SDSS-Survey (GASS) * The GALEX Arecibo SDSS Survey - I. Gas fraction scaling relations of massive galaxies and first data release ** Catinella, Schiminovich, Kauffmann, Fabello, Wang et al. 2010, MNRAS ** We also find that the fraction of galaxies with significant (more than a few per cent) HI decreases sharply above a characteristic stellar surface mass density * The GALEX Arecibo SDSS Survey - II. The star formation efficiency of massive galaxies ** Schiminovich, Catinella, Kauffmann, Fabello, Wang et al. 2010, MNRAS ** Both of these populations are plausible candidates for `transition' galaxies, showing potential for a change (either decrease or increase) in their sSFR in the near future. * The GALEX Arecibo SDSS survey - III. Evidence for the inside-out formation of Galactic discs ** Wang, Kauffmann, Overzier, Catinella, Schiminovich, Heckman et al. 2011, MNRAS ** Our results are consistent with the ‘inside-out’ picture of disc galaxy formation, which has commonly served as a basis for semi-analytic models of the formation of discs in the context of cold dark matter cosmologies. The lack of any intrinsic connection between H I fraction and galaxy asymmetry suggests that gas is accreted smoothly on to the outer disc. * The GALEX Arecibo SDSS Survey - IV. Baryonic mass-velocity-size relations of massive galaxies ** Catinella, Kauffmann, Schiminovch, Lemonias, Scannapieco, Wang et al. 2012, MNRAS ** We find that discs and spheroids are offset in the stellar dispersion-size relation, and that the offset is removed when corrected dispersions are used instead. The generalized BFJ relation represents a fundamental correlation between the global dark matter and baryonic content of galaxies, which is obeyed by all (massive) systems regardless of morphology. * The GALEX Arecibo SDSS Survey. V. The Relation between the H I Content of Galaxies and Metal Enrichment at Their Outskirts ** Moran, Heckman, Kauffmann, Dave, Catinella, Brinchmann, Wang et al. 2012, ApJ ** We argue that much of the recent stellar mass growth at the edges of these galaxies can be linked to the accretion or radial transport of relatively pristine gas from beyond the galaxies' stellar disks. * The GALEX Arecibo SDSS Survey. VI. Second data release and updated gas fraction scaling relations ** Catinella, Schiminovich, Kauffmann, Fabello et al. 2012, A&A ** Having more than doubled the size of the sample since the first data release, we also revisit the main scaling relations of the Hi mass fraction with galaxy stellar mass, stellar mass surface density, concentration index, and NUV - r color, as well as the gas fraction plane introduced in our earlier work.